A:
There are those who suspect Wildflower Center volunteers are the culpable
and capable culprits. Yet, others think staff members play some, albeit small, role. You
can torture us with your plant questions, but we will never reveal the Green
Guru's secret identity.

rate this answer

Thursday - June 20, 2013

QUESTION:

Petals on calycanthus develop black spots the turn into holes. Problem appears shortly after buds open. Occurs every year. Foliage is healthy. Plant growing well and doubles or triples size every year. Has been in present location about four years.

"Growing Conditions

Please note the comment on leaf burn, if the site is too dry, as well as the need for sun (6 hours or more of sun a day) or part shade (2 to 6 hours of sun), but that is referring to leaves, and we assume you are finding the spots on the petals of the flowers. So, we will look further and see if we can find an explanation of the spots on blossoms.

Here is more information and pictures from Las Pilitas Nursery in California. From that, we learned that pollination is by members of the Nitidulidae family of beetles. Further research said that these are sap sucking beetles, and we could not find any indication that they did damage to flowers they were pollinating.

All the references we searched said that the plant was relatively pest and disease free. Since, as you say, the plants are healthy, we would not be too worried about it. We are native plant gardeners, not entomologists, but if you are concerned, you might contact the Washington State University Extension Office for Pierce County to see if other similar occurrences have been reported in your area.

From the Image Gallery

More Pests Questions

Getting rid of Aphids on Asclepias plants in Brea, CA.July 23, 2012 - I grow asclepsias or MILKWEED for the benefit of Monarchs. At times I have aphids consuming the leaves. How can I destroy the aphids without harming the Monarch eggs?
Thank you very much.
view the full question and answer

Tulip tree with white spots on leaves in MississippiJuly 31, 2008 - I have a tulip tree in my yard that blooms in the spring that is about 10-15 years old. However just this past week or so we have noticed that there is lots of white spots on the leaves and the branc...view the full question and answer

Is oak leucanium an invasive species in Texas from Laredo TXApril 02, 2013 - Is Parthenolecanium quercifex considered an invasive species in Texas? Does this insect attach itself to redbuds? I spotted and removed from my small 5ft Texas Redbud last year. It seems that it has ...view the full question and answer

Mealy bugs on plants in Washington, DCJuly 07, 2011 - Dear Mr. Smarty Plants,
There is this white stuff, looking like snow flakes, that is attacking my office plants. I use gasduster to blow it off of them, but that does not stop it from reappearing. Wh...view the full question and answer

Plants to repel mosquitoes from Leander TXMay 19, 2013 - What are the best plant for repelling mosquitoes in the Leander area? The land here is hilly and rocky.
view the full question and answer